This invention relates to a device for momentarily working a sample by a single pulse of electron beams. In other words, this invention relates to a pulsed electron beam device for processing a sample by pulsed electron beams. Although a semiconductor wafer will be described as the sample throughout the instant specification, the samples may be other things as, for example, ceramics or the like.
On fabricating a semiconductor device on a semiconductor wafer, ion implantation is often carried out to form a shallow impurity area adjacently of a surface of the wafer. Such ion implantation inevitably gives rise to distortion or defects in crystal structure of a surface region of the wafer. The defects in crystal structure deteriorate characteristics of the fabricated semiconductor device. To temper the defects in crystal structure, the surface region of the wafer may be annealed by heat treatment. However, such heat treatment should rapidly be carried out in a very short duration of, for example, 1 microsecond or less. Otherwise, diffusion unfavorably takes place from the impurity area during the heat treatment.
A pulsed electron beam device is suitable for momentarily processing the wafer to temper the crystal defects without any diffusion. With the electron beam device, it is preferable that the whole of the surface region is uniformly processed by electron beams at a time. In other words, the electron beams should uniformly be emitted to the whole surface region with uniform electron density. For this purpose, a conventional pulsed electron beam device is supplied with high voltage more than 100 kilovolts as will later be described with reference to one of a few figures of the accompanying drawing. Handling of the device is troublesome owing to such high voltage. Moreover, only a little of the high voltage contributes to generation of the electron beams. Efficiency has therefore been very low.